In Silico Identification and In Vitro and In Vivo Validation of Anti-Psychotic Drug Fluspirilene as a Potential CDK2 Inhibitor and a Candidate Anti-Cancer Drug

Abstract

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. Surgical resection and conventional chemotherapy and radiotherapy ultimately fail due to tumor recurrence and HCC’s resistance. The development of novel therapies against HCC is thus urgently required. The cyclin-dependent kinase (CDK) pathways are important and well-established targets for cancer treatment. In particular, CDK2 is a key factor regulating the cell cycle G1 to S transition and a hallmark for cancers. In this study, we utilized our free and open-source protein-ligand docking software, idock, prospectively to identify potential CDK2 inhibitors from 4,311 FDA-approved small molecule drugs using a repurposing strategy and an ensemble docking methodology. Sorted by average idock score, nine compounds were purchased and tested in vitro. Among them, the anti-psychotic drug fluspirilene exhibited the highest anti-proliferative effect in human hepatocellular carcinoma HepG2 and Huh7 cells. We demonstrated for the first time that fluspirilene treatment significantly increased the percentage of cells in G1 phase, and decreased the expressions of CDK2, cyclin E and Rb, as well as the phosphorylations of CDK2 on Thr160 and Rb on Ser795. We also examined the anti-cancer effect of fluspirilene in vivo in BALB/C nude mice subcutaneously xenografted with human hepatocellular carcinoma Huh7 cells. Our results showed that oral fluspirilene treatment significantly inhibited tumor growth. Fluspirilene (15 mg/kg) exhibited strong anti-tumor activity, comparable to that of the leading cancer drug 5-fluorouracil (10 mg/kg). Moreover, the cocktail treatment with fluspirilene and 5-fluorouracil exhibited the highest therapeutic effect. These results suggested for the first time that fluspirilene is a potential CDK2 inhibitor and a candidate anti-cancer drug for the treatment of human hepatocellular carcinoma. In view of the fact that fluspirilene has a long history of safe human use, our discovery of fluspirilene as a potential anti-HCC drug may present an immediately applicable clinical therapy.

Cyclin-Dependent Kinase 2 Promotes Tumor Proliferation and Induces Radio Resistance in Glioblastoma

“…Among all the CDKs, CDK2 was identified as a key kinase in tumorigenesis and proliferation in a range of cancer types including lung cancer, liver cancer, colon cancer and breast cancer [11], [12], [13]. In this study, we identified CDK2 expression was significantly elevated in glioma tumor especially in GBM and was functionally required for GBM cell proliferation and tumorigenesis.…”

“…Another study showed that inhibition of CDK2 kinase activity reduced tumor proliferation via selectively targets the CD44 + /CD24 −/Low stem-like cells in triple-negative breast cancer when combined with conventional chemotherapy [11]. Additionally, a newly published study demonstrated that CDK2 inhibitor exhibits anti-cancer effect in human hepatoma HepG2 and Huh7 cells and significantly inhibited tumor growth [12]. Lim et al identified CDK2 as a direct therapeutic target of curcumin in colon cancer cells via cell cycle arrest in HCT116 cells [13].…”

Discovery of rafoxanide as a dual CDK4/6 inhibitor for the treatment of skin cancer

“…Subsequently, the structures of 3,167 approved drugs were gathered from the ZINC database (28,29). To predict the binding conformations and the binding affinities of these drugs with the CDK4/6 proteins, the free and popular docking software idock v2.2.1 (20,21) was used to dock all of the compounds onto all of the CDK2/4/6 structures. Prioritized in accordance with the average predicted binding affinity, 9 commercially available compounds were identified, purchased and subsequently evaluated.…”

“…Using structure-based virtual screening via protein-ligand docking to select candidates from FDA-approved smallmolecule drugs, we previously identified two CDK2 inhibitors, adapalene (20) and fluspirilene (21). In the present study, we attempted to identify drugs with the ability to specifically inhibit both CDK4/6 at the same time without affecting CDK2.…”

PS4DR: A multimodal workflow for identification and prioritization of drugs based on pathway signatures

“…Interestingly, we also have two drugs, Olmesartan, for hypertension, and Fluspirilene, for schizophrenia, from very different therapeutic areas in our shortlist. While no reports of their potential role in melanoma treatment have been found yet, numerous studies have suggested their applicability in different cancer treatments(Masamune et al, 2013;Abd-Alhaseeb et al, 2014;Shi et al, 2015;Patil et al, 2015).…”